1. Field of the Invention
The invention relates to foundry practice, and more particularly to installations for electrohydroblasting of castings to remove core and moulding sands by using an electrohydraulic effect.
The term "electrohydraulic effect" is used to denote the action upon a solid body of pulse pressures induced by a high-voltage discharge in a liquid.
2. Description of the Prior Art
Among means intended for cleaning castings (in particular large ones, weighing from 100 to 40,000 kg and over) of core and moulding sands, distinguished for their high throughput capacity, economic performance, capability for practically complete cleaning of variously shaped castings are electrohydroblasting installations comprising generally a base, a bath placed on the base, a mechanism for feeding castings into the bath, an electrode, a mechanism for introducing the electrode into the bath and a pulse current generator coupled electrically with the electrode (see, for example, the British Pat. No. 1,303,223). However, working conditions for personnel tending to these installations are not very favorable, as the high-voltage discharges give rise to a high level of noise, vibrations and a pulse magnetic field, all having a harmful effect upon personnel.
More favorable working conditions are provided at an installation for electrohydroblasting of castings (see Gulyi G. A., Oborudovaniye i tekhnolgicheskiye protsessy s ispolzovaniem elektrogidravlicheskogo effekta /Equipment and Technology Using the Electrohydraulic Effect/, Machinostroeniye Publishers, Moscow, 1977, pp.58-59) which includes an insulated casing formed with a brickwork having doors through which castings are transported to a mechanism for feeding them into a bath. The insulated casing is mounted on a base over the bath and encloses the mechanism for feeding castings into the bath, the electrode, the mechanism for feeding the electrode into the bath and a pulse current generator coupled electrically with the electrode.
In the known installation, the protective insulated casing partly absorbs vibration noise, but fails to guard altogether service personnel against the harmful effect of the pulse magnetic field. In addition, the brickwork has no sufficient resistance to large impact wave loads induced by high-voltage discharges.